Comparing the effect of non-medical mechanical restraint preventive factors between psychiatric units in Denmark and Norway ZoffmannVibeke Dirk SiersmaVolkert BakJesper Maria SestoftDorte AlmvikRoger Brandt-ChristensenMette 2015 <div><p></p><p><i>Background:</i> The use of mechanical restraint (MR) is controversial, and large differences regarding the use of MR are often found among countries. In an earlier study, we observed that MR was used twice as frequently in Denmark than Norway. <i>Aims:</i> To examine how presumed MR preventive factors of non-medical origin may explain the differing number of MR episodes between Denmark and Norway. <i>Methods:</i> This study is a cross-sectional survey of psychiatric units. Linear regression was used to assess the confounding effects of the MR preventive factors, i.e. whether a difference in the impact of these factors is evident between Denmark and Norway. <i>Results:</i> Six MR preventive factors confounded [∆exp(<i>B</i>)> 10%] the difference in MR use between Denmark and Norway, including staff education (− 51%), substitute staff (− 17%), acceptable work environment (− 15%), separation of acutely disturbed patients (13%), patient–staff ratio (− 11%), and the identification of the patient's crisis triggers (− 10%). <i>Conclusions:</i> These six MR preventive factors might partially explain the difference in the frequency of MR episodes observed in the two countries, i.e. higher numbers in Denmark than Norway. One MR preventive factor was not supported by earlier research, the identification of the patient's crisis triggers; therefore, more research on the mechanisms involved is needed. <i>Clinical implications:</i> None of the six MR preventive factors presents any adverse effects; therefore, units in Denmark and Norway may consider investigating the effect of implementing, the identification of the patient's crisis triggers, an increased number of staff per patient, increased staff education, a better work environment and reduced use of substitute staff in practice.</p></div>